Composition of polyolefin, polystyrene and block of said polymers

ABSTRACT

This invention concerns a process for obtaining homogeneous polymer compositions containing at least one olefin polymer and/or one arylvinyl polymer. The process consists of adding, to either or to a mixture of both of these polymers, one or more block copolymers, containing one polyolefin and one polyarylvinyl sequence. These polymer compositions provide homogeneous substances with properties combining those of the individual polymers, and in some mixtures these properties are considerably improved as the result of synergic phenomena.

United States Patent 1 1 I 1 1 3,894,117

Agouri et al. 5] July 8, 1975 COMPOSITION OF POLYOLEFIN, 3,203,937 8/1965 Breslow et a1. 260/889 POLYSTYRENE AND BLOCK 0F SAID 3,424,649 l/l969 Nyberg et 21.... 260/876 B POLYMERS 3,478,129 11/1969 Kern et a1. 260/878 B 3,522,036 7/1970 Vest et al.... 260/878 R [75] Inventors: Elias Agouri, Pau; Raymond Catte, 3,652,725 3/1972 Diaz et al. 260/876 B Billere; Jean-Louis Dauba, Pau, all of France Primary ExaminerMurray Tillman Assistant Examiner-J. Ziegler [73] Asslgnee: Aqultame Total Orgamco Pans Attorney, Agent, or FirmOstrolenk, Faber, Gerb &

France Soffen [22] Filed: Dec. 23, 1971 [21] Appl. No.: 211,667 [57] ABSTRACT This invention concerns a process for obtaining homo- [30] F i A li i p i i D geneous polymer compositions containing at least one Dec. 29 1970 France 70.47018 Olefin polymer and/or one arylvinyl polymer The process consists of adding, to either or to a [52] US. Cl. 260/876 B; 161/4 B; 215/200; mixture of both of these polymers, one or more block 260/878 B; 260/897 A; 260/897 B Copolymers, containing one polyolefin and one [51] Int. Cl. C08f 19/04 polyarylvinyl sequence. [58] Field of Search 260/876 R, 876 B, 878 R, These polymer compositions provide homogeneous 260/878 B, 886, 897 R, 897 A, 897 B substances with properties combining those of the individual polymers, and in some mixtures these References Cited properties are considerably improved as the result of UNITED STATES PATENTS synergic phenomena. 3,177,270 4/1965 Jones et a1. 260/876 3,189,665 6/1965 Nozaki 260/878 B 7 Clams Drawmgs COMPOSITION OF POLYOLEFIN, POLYSTYRENE AND BLOCK OF SAID POLYMERS This invention concerns a process for preparing homogeneous polymer compositions containing at least one polymer from the olefin and arylvinyl group, and in particular a mixture ofan olefin polymer, such as polyethylene or' polypropylene, with an'arylvinyl polymer, such as polystyrene. It also concerns thepolymer compositions obtained by this process. I L

There is an obvious advantage in substances which combine the properties of polyolefins' with certain properties of polystyrene, particularly its rigidity and suitability as a printing base.

However, because of the incompatibility of polyolefins and polystyrene, composites of these polymers are heterogeneous in structure and mechanically weak, so that it is little use preparing them.

Research has now revealed a process for obtaining, among other things, homogeneous mixtures of polyolefins and polystyrene.

The process according to the invention, for the preparation of homogeneous polymer compositions containing at least one polymer from the olefin and arylvinyl group, is characterized by the fact that the polymer is mixed intimately with one or more block copolymers containing one polyolefin and one polyarylvinyl sequence.

In one embodiment of the invention, at least one of the block copolymers includes a sequence formed from the polymer to which it is added.

In another embodiment of the invention, the block copolymer or copolymers are added to a mixture of an olefin polymer and arylvinyl polymer, and each contains one sequence formed from the olefin polymer and another sequence formed from the arylvinyl polymer.

\ acetate copolymers.

In another embodiment of the invention, the arylvinyl polymers are one or more polymers obtained by polymerizing or copolymer'izing styrene or styrene derivatives.-

In another embodiment of the invention, the polymers consist of polyethylene and polystyrene, and the block copolymer is formed from one sequence of each of them.

In another embodiment of the invention, substances such as fillers, stabilizers, plasticizers, organic or inorganic pigments, opaquing agents, or even another polymer, are added to the polymer or mixture of polymers before or after the block copolymer is added.

In another embodiment of the invention, the block polymer is added in a molten state, using a screw mixer, internal mixer or stirrer reactor.

In another embodiment of the invention, the block copolymer is added by mixing dry powders 0r granules of the polymer or polymers and of the block copolymer.

In another embodiment of the invention, the block copolymer is added to the polymer or polymers in solution.

This invention also concerns the homogeneous polymer compositions obtained by this process.

It also concerns films, plates, flat or corrugated sheets, sheaths, pipes, bottles and other manufactured articles obtained from these polymer compositions.

Other aims and benefits will appear from the following examples of various embodiments of the invention,

The block copolymers used in the invention can be obtained by first polymerizing an olefin in the presence of dialkyl-zinc and co-ordinating catalysts and then polymerizing the arylvinyl monomer, using a radical-type catalyst, in the presence of the non-deactivated polymer produced during the first stage.

In one embodiment of the invention, the block copolymer is added by being mixed in a moltenstate with one of the polymers, after which the remaining polymer or polymersare added to this mixture.

In another embodiment of the invention, the block copolymers are'added to the polymer or a mixture of polymers by being mixed in a molten state.

In a recommended embodiment of the invention, the block copolymer of copolymers are added to the mixture of polymers by being mixed in a molten state, under temperature and shearing conditions atwhich the polymers have similar viscosities.

In-another embodiment of the invention, the block polymer is added to a mixture of from'50 to 100 of one polymer and from 50 to 0 of another polymer.

In another embodiment of the invention, between 1 and 400, and preferably 5 and 200, parts of block co-'* propylene, polybutene, polymethylpentene, ethylene/ propylene block copolymers, polyallomers, and olefin which, however, is not confined to them.

To simplify matters, polyethylene will be referred to below as PE, and polystyrene as PS. In most cases, the exact trade names of these substances are given in brackets. Manolene 6001 is a high-density PE with a density of 0.96 and melt index of 0.1, and Lacqtene 1020 is a low-density PE with a density of 0.92 and melt index of 2. Lacqrenes are crystal PEs marketed by the applicants assignee. Polymer compositions according to the invention may be used to manufacture extruded sheaths (thin films or sheets to replace paper, corrugated sheets to replace cardboard) or hollow tubing (pipes or cables), or heat-shaped or injected articles (bottles).

For example, PE/PS/block PE.PS compositions in the form of thin sheets can usefully replace paper, since the very fine dispersion of PS in the PE matrix gives the material touch, printing, tear-strength, flexibility and welding properties lacking in'composites that do not contain any block copolymer.

Sheets of excellent quality for printing work can be obtained from composites containing 5 to 30 weight of block copolymers, 2 to 40 PS, and the rest PE, and possibly including titanium oxide, without any preliminary treatment.

Composites with a higher block copolymer content, and particularly low density polyethylene containing 20 to 5( weight of block copolymers, can be used to make articles such as bottles and pipes, which have great rigidity, not unlike that of high-density polyethylene. Composites containing these block copolymers are also found to congeal more quickly when molten than polyethylene, so that extrusion, injection and heat-shaping processes can be speeded up.

EXAMPLE 1 The products are mixed in a double-screw welding Table 2 extruder, in which the screws rotate at a speed of 100 Mixture C D rpm. The mixing temperature is 200C. I 5 S f f S f Rough The extruded product 18 granulated and in ected mto gag-teat in gl( 1) (AST( 709.62T) 33.5 1 5 0 rea ing e ongation a Battenfeld 10 VP.25 plasttctzer screw press. Breaking strength in kg/Sqfln (3) 160 160 Two mixtures are prepared. Mixture A contains 12.5 Welding properties Good Poor parts weight of PE (Manolene 6001 12.5 parts crystal Pr'mmg qualmes p y y (.Lacqrene and parts block 10 (l For guidance. the dart-test result for a sheet of paper is g. copolymer Wlth weight Of (2) Measured parallel to direction of extrusion.

Mi B contains parts igh f (M (3) The breaking strength is the ultimate strength in the zone of elasticity. lene 6001), and 27.5 parts PS (Lacqrene). EXAM 3 Table l below shows the mechanical properties of PLE each of these polymer compositions. 15 Using the technique described in example 2 for mixture C, four more mixtures are prepared. Table 3 shows Table 1 the compositions of these mixtures by percentage weight.

Yield Impact Dynstat Mixture point Breaking tension bending Table 3 kg/sq.cm. elongation kgcm/sq.cm kg/mm I Mixture PE (Lacqtene PS (Lacqrene PE/PS block A 370 54 270 7.4

1020) 550) copolymer with B 369 27 95 5.6 17 PS E 65 0 35 F 73 l2 15 In addition, microphotographic examination, using S g8 g8 g8 hot-pressed cross-sections cut with a rnicrotome, 15 p.

Table 4 Mixture Dart-test Breaking Breaking Welding Appearance of in g strength elongation properties sheets in kg/sq.cm (l) E 106 150 370 Excellent Very smooth F 60 130 295 Excellent Very smooth G 215 46 Good Soft H 20 325 60 Good Slightly rough (I Measured parallel to direction of extrusion.

thick, shows that the ternary mixture is much more homogeneous-v than the binary mixture.

EXAMPLE 2 Using th'e same technique as in example 1, two more mixtures are prepared, with the following compositions byweightz Mixture C: 60 PE (Lacqtene 1020); 17.7 PS (Lacqrene 550); 22.3 PE/PS block copolymer containing 17 PS; I

Mixture D: 60 PE (Lacqtene 1020); 24 PS (Lacqrene 550); 16 PE (Manolene 6001).

In the case of mixture C, the block copolymer is first mixed with the PS, and the resulting mixture added to the PE. i

Microscopic examination reveals the excellent dispersion of PS in mixture C, compared with mixture D (grains 3p. for C, 10 to 100 y. for D). i

The two mixtureswere extruded into sheaths with maximum encouragement of bi-orientation (width 50 to cm; thickness 10/100ths mm).

Table 2 shows the properties of these sheaths.

Microscopic examination shows the excellent dispersion of the PS in these mixtures.

The mixtures were extruded into sheaths 1/10 mm thick, with an expansion rate of 3.

Table 4 shows the properties of the sheaths.

The thin sheets obtained from these mixtures resemble paper, with regard to printing qualities and surface feel. In addition, the sheets obtained from mixture H have the same tearing and crumpling qualities as highquality paper. No blocking occurred in any of the sheets.

Each of these mixtures is extruded, using a die imitating the cross-section of corrugated cardboard. The resulting products have high compressive strength, weigh 400 to 650 g/sq.m depending on thickness, and show permanent deformation when folded.

Containers are also produced by extrusion-blowing, using a 6 cm-diameter die. The bottles obtained have good join-lines, satisfactory appearance, and high rigidity. v

Test-samples produced from these mixtures show high surface-cracking strength, measured in accordance with ASTM standard D 1693. The Vicat temperatures are 100C for mixture E, 91C for F, 95C for G and 97C for H. (In comparison, the Vicat temperature of low-density polyethylene, measured under the same conditions, is 90C.)

Tubing, measuring 6 X 8, is also extruded using mixture E. The tube has excellent rigidity, and a remarkably smooth appearance. Bursting strength at C is at least twice that of polyethylene tubes produced under the same conditions.

In addition, all these composites are much easier to extrude, and can be drawn much faster.

EXAMPLE 4 Using the same mixing technique as for example 1, two more mixtures are prepared, mixture I, consisting of 99.4 weight of ethylene/vinyl-acetate copolymer with 5 vinyl acetate, and 0.6 PE/PS block copolymers with 20 weight of PS, and mixture J, consisting of 99.7 weight of the same ethylene/vinylacetate copolymer as in mixture 1, and 0.3 silica gel, normally used as an agent to reduce post-extrusion blocking between sheaths made from ethylene polymers and copolymers.

The two mixtures, and the original ethylene/vinylacetate copolymer (K), are extruded in sheaths approximately 50 cm wide and 0.05 mm thick, and tested.

Table 5 shows the results of these tests.

(2) Force in grams needed to detach two superimposed sheaths.

These results show that the addition of the PE/PS block copolymer to the ethylene/vinylacetate copolymer considerably reduces post-extrusion blocking, while altering the optical and mechanical properties of the ethylene/vinylacetate copolymer as little as possible.

Polyolefin/polyarylvinyl and particularly polyethylene/polystyrene block copolymers therefore act as an anti-blocking agent in olefin polymers such as polyethylene, or olefin copolymers such as ethylene/vinylacetate copolymer, used to manufacture extruded sheaths and films.

When less than 10 weight of block copolymer is added to polyolefins or olefin copolymers, such as ethylene/vinylacetate copolymer, the block copolymer confers considerable slipping power on the films and sheaths manufactured. In other words, the block copolymer can be used to replace the slip agent, such as fatty amide, normally used for this purpose.

Naturally, the invention is in no way confined to these examples: many alternative forms are possible, for someone skilled in the art, depending on the applications involved, without any departure from the spirit of the invention.

What is claimed is:

l. A homogeneous polymer composition comprising a monoolefin polymer, polystyrene, and at least 1 polymonoolefin-polystyrene block copolymer containing 1 polymonoolefin and l polystyrene sequence.

2. The homogeneous polymer composition of claim 1 wherein said block copolymer is present in an amount between 1 and 400 parts per hundred parts of said monoolefin polymer and polystyrene.

3. The homogeneous polymer composition of claim 2 wherein said block copolymer is a block copolymer of polyethylene and polystyrene.

4. The homogeneous polymer composition of claim 1 comprising polyethylene, polystyrene, and a polyethylene-polystyrene block copolymer.

5. The homogeneous polymer composition of claim 4 containing 5 to 30 weight block copolymer, 2 to 40 weight polystyrene, and the balance polyethylene.

6. The homogeneous polymer composition of claim 1 wherein the amount of block copolymer is less than 10 weight 7. The homogeneous polymer composition of claim 1 in the form of a film, plate, sheath, flat or corrugated 

1. A HOMOGENEIOUS POLYMER COMPOSITION COMPRISING A MONOOLEFIN POLYMER POLYSTRYENE, AND AT LEAST 1 POLYMONOOLEFIN-POLYSTYRENE BLOCK COPOLYMER CONTAINING 1 POLYMONOOLEFIN AND 1 POLYSTYRENE SEQUENCE.
 2. The homogeneous polymer composition of claim 1 wherein said block copolymer is present in an amount between 1 and 400 parts per hundred parts of said monoolefin polymer and polystyrene.
 3. The homogeneous polymer composition of claim 2 wherein said block copolymer is a block copolymer of polyethylene and polystyrene.
 4. The homogeneous polymer composition of claim 1 comprising polyethylene, polystyrene, and a polyethylene-polystyrene block copolymer.
 5. The homogeneous polymer composition of claim 4 containing 5 to 30 weight % block copolymer, 2 to 40 weight % polystyrene, and the balance polyethylene.
 6. The homogeneous polymer composition of claim 1 wherein the amount of block copolymer is less than 10 weight %.
 7. The homogeneous polymer composition of claim 1 in the form of a film, plate, sheath, flat or corrugated sheet, tube or bottle. 